Method and apparatus for fusing metals



Feb. 18, 1936. J. A. ZUBLlN METHOD AND APPARATUS FOR FUSING METALS FiledAug. 6, 1934 JOHN A. ZUBLIN INVENTOR 7W ATTORNEY Patent ed Feb. 1a, 1936a 2,031,088

UNITED STATES iATENT OFFICE.

John A. Zublin, Bel Air, Calif.

' Application August 6, 1934, Serial No. 738,684

5 Claims. (Cl. 75-225) The. present invention has to do with methodsthere is no time required for the transfer of the and apparatus forfusing metals to produce a' molten material from a crucible to a mould.relatively uniform body from constituents that do Another object is toprovide method and appanot readily mix or dissolve one in another. Asratus which are not critical in their operations aspecific example ofthe invention, thereisshown as regards the state of division or theparticle 5 apparatus adapted to making alloy welding rods, size of thecharge to be melted, but which can be since the apparatus has beendeveloped with this operated successfully with a finely powdered end inview; but it is to be understood that the charge or with one comprisingrelatively large invention in its broader aspects is not limitedparticles, or, with a mixture of large and small to this specific deviceor this particular use, for grains. it may be embodied in devicesadapted to other A further object is to provide a device with uses whichthe quantity, intensity, and duration of It has been common practice tomelt met'als heating can be readily controlled according to the toeifect a solution or mixing of them while in quantity and physicalcharacteristics of the the liquid state, but such practice is notadapted charge to be melted, in order to secure proper It those metalswhich do not i w quid, rate of melting, time of liquification, andtemsuch as iron and copper which are very sparingly perature of melting,and in which the heat can soluble in each other and, at certaintemperabe locally concentrated to effect fusion of subtures, immiscible.Another example is lead and stances of high melting point. e I zinc.when these first two metals are subjected These objects are attained inan apparatus to the conventional methods of melting in a .embodying myinvention, that comprisesamould, crucible and then pouring into a mould,there is in the shape of the final product, adapted to renecessarilysufflcient elapsed time for the metals ceive the charge of mixed metals.At least one to separate, and the casting contains the undiswall of themould is an electrical conductor or solved copper in' a few largesegregations that electrode, and a second electrode is'adapted forresult in a decidedly non-uniform product. movement into arcing relationwith the mould 'I have found, however, that if the constituents,electrode so that the are between them passes 8 t" bein! intimatelymixed, are melted and subthrough the substance to be fused, the twoelecsequently cooled so rapidly that separation cantrodes being capable"of relative movement 50' not occur, the resulting product issubstantially that the arc may be moved on away from the uniform andcontains the elements in quantities molten chargeto progressively fusethe remainder in excess of the amounts that can be mutually of thecharge. dissolved. The total time involved is very short The finalproduct contains the undissolved exso that the metals are not fluid longenough to cess of a metal in small particles dispersed separate; alsolosses by oxidation and vaporizathroughout the remainder of the metals,similar tion are kept low by reducing the duration of to being embeddedin a matrix.' In this respect exposure to high temperatures. the productis similar to a sintered product, but The invention has as its generalobject the the process is more nearly true melting since all fusingtogether of metals which do not easily constituents'will normally meltatthe"tempera-' 40 mix or dissolve in one another and the congealing turesavailable, except possibly in case a difiof these fused metals to-form asolid unitary cultly fusible substance such as tungsten carbidebody ofsubstantially uniform composition and is used with a metal of much lowermelting point distribution of the constituent metals, the metals and itis not necessary or desirable to fully melt being present in excess ofquantities that can be the constituent of highest fusion point.Thedissolved. composition and character of a typical product A secondobject is a method of obtaining a uniare described more fully in mycompanion "appliform distribution of the constituents when the cationentitled Alloy and method of maldng molten state is reached, and .ofcooling the melt same, Serial No. 738,683,1lled on even date hereto astable condition before the distribution of the with, and which may bereferred to for further metals has become non-uniform because ofsepdescription of the physical characteristics of a aration of oneconstituent into a few large bodies. typical product. I

Another object of the invention is. to provide How these and otherobjects and advantages of means in which the metals may be fused but myinventionare attained will-be' more easily which also has mouldcharacteristics so that understood fro'mthe following description of-a mpreferred and typical form of apparatus, and the annexed drawing, inwhich:

Fig. 1 is an end view, with portions broken away, of a deviceconstructed in accord with my invention;

Fig. 2 is a longitudinal vertical section on line 2-'-2 of Fig. 1; i

Fig. 3 is a diagrammatic plan of a revolving table carrying a pluralityof the units illustrated in Fig. 1; and

Fig. 4 is a diagrammatic perspective, of a variational form ofvapparatus.

Inasmuch as a thorough understanding of the rests base plate I2 of amould unit. Attached to the base plate in any suitable way is aplurality of triangular blocks arranged. in opposed pairs I8 and I4 sothat the upper oppositely inclined faces of the pairs present a generalV- formation upon which rests the cylindrical electrode generallyindicated at I5. The electrode assembly I5 comprises a centralcylindrical member l8 and a pair of discs I1 carried one at each end ofcylinder I6 and held in place by bolt I8 as illustrated in Fig. 2. Ifdesired, discs II can be formed integrally with cylinder I8 as terminalA pair of bricks 20 are so placed that their inner longitudinal edgesrest upon the top of cylinder I8 and present opposed faces 20a spaced ashort distance apart, The bricks are of the same length as cylinder I8and fit in between discs II. In this way, the bricks and electrodeassembly I5 form an elongated mould or charge receiving space 22 on topof cylinder I8, of which mould, faces 28a form the side walls, cylinderI6 forms the bottom wall, and discs I! form the end walls. Since thecharge is melted while in space 22, this space is in the nature of. acombined crucible and mould to shape the final product. The outer edgesof the bricks are supported by posts 24 threaded into standards 25secured to base I2. Base I2 and the lower portions of standards 25*arecounter-bored as at-26 to receive posts 24 so that the latter'may beadv:Iusted vertically by simple rotation to properly position bricks 20.In this way the bricks may be suitably adjusted to any size of cylinderI6, and the bricks may be moved toward or away from each other to alterthe size-and shape of space 22 so that the mould formed thereby will beof the desired shape.

For reasons that will be more evident,v it is preferred that cylinder I6be of electrically conductive material, and for this purpose carbon ispreferred since it has a relatively high melting point. Bricks 20 may beof any suitable material, and it is preferred that they be ofelectrically non-conductive material since during the application of theelectric arc, to be described later, the

. arc is likely to short across to" the bricks rather than pass throughthe charge in space 22 and then to electrode I5. As it is suflicientthat only onewall of the mould be an electrode, the bricks ZO-meshscreen.

- ticles.

are preferably of some refractory material which is not likely tocombine with the materials that are fused.

Although the electrode I5 may have a cross "section other than circular,a generally circular cross sectionis preferred because, after thesurface of cylinder. has become rough and pitted from use, a selectednew surface may be brought into the top position to act'as'the mouldwall by simply rotating the entire electrode, and, being circular, itwill rest on blocks I3 and I4 equally well in any position. Furthermore,the periphery of cylinder I6 may be provided with indentations or otherconfigurations designed to shape the final product, and when theelectrode is circular or approximately so it is easily possible to bringselected portions of the electrode into operative position by rotatablyadjusting it on its supports.

A movable electrode is provided in the form of .carbon pencil 28 held inclamp 29 on handle 38 so that it may be grasped by an operator and movedlengthwise of mould 22. Electrode 28 is an ordinary carbon pencil ofrelatively small area as compared with the total area of space 22 sothat the are passing between the two electrodes is concentrated in asmall space. and the total" heat of the electric current is localized.As will be understood, it is not'necessary that this upper electrode bemanually movable, for mechanical control means may be used. Or thepencil may be stationary and the lower electrode movable. since anyarrangement which secures relative movement between the two electrodeswill provide an are which moves along the entire mould.

The electrical power is direct current supplied from any suitable sourceby negative lead 32 attached to electrode 28 and positive lead 83attached to binding post 34 on base plate I2, the current passing toelectrode li'through wedges I3 arid I4.

' The present process is not limited to a specific composition ofmaterial, any suitable substances being placed in mould 22. For makingmy alloy welding rods, I prefer to use a composition comprising coppermixed with a ferrous base which may be iron and/or various ferro-alloyssuch as ferro-chromium, term-molybdenum, and the like, 'the copper beingpresent in amounts greatly in excess of the amount soluble in theferrous base. A typical composition is shown by the following tableshowing the range in parts by weight of the constituents:

The alloy produced is described in my copending application Ser. No.738,683.

However, it has been found preferable to comminute the metals to agranular form in which the grains are, preferably, generally uniform insize and about as large as will pass through a This grain size isselected to help obtain a closely uniform product, and is .notlimitative upon the charge used, for the de= vice has been operatedsuccessfully with particles as large in cross section as the final rod,and also with a mixture of large and small par- The charge may alsocomprise one or more wires or rods laid lengthwise of space 22 to bemelted, into 'the final product, thus indicat- Laos 1,088

ing the device operates equally well over a range of sizes or with mixedsizes of particles in the charge.

In making welding rod, better ro is obtainedwith a more uniformcomposition. It is not essential that each fraction of a cross sectionhave the same identical composition, but what is sought is to" have eachshort length of the rod of substantially the same average composition.This is done by uniformly distributing the particles of each constituentthrough the charge by some mixing device, a preferred one being a ballmill because of the uniformly fine distribution ob- ,tained. Of coursethe finer particle sizes lend themselves to a better distribution, and.help in maintaining a uniform quality of product.

After suitable mixing of the constituents, a proper amount of themixture is introduced into the mould. With electrode 28.jan arc is thenstruck at one end of-the mould, the current passing through the mixtureto electrode IS. The intense heat of the are rapidly melts the powderedmaterials beneath pencil 28 and surrounding the are passing through themixture, and as rapidly as a portion of the, material melts in one spotthe arc is moved away from the molten charge and over unmelted charge sothat the entire charge is progressively melted from one end to theother. The masses of bricks 20 and electrode.

I! are relatively large and are not appreciably heated during the shortexposure to the arc. Consequently the heat flows rapidly out of thefused substance into the cooler mould walls where it is dissipated. Inthis way the fused substance is quickly congealed and chilled to,relatively low temperature. Thus there arein the mould at the same timethree stages ,of the product; the congealed solid 36 behind theelectrode, the fused substance 81 beneath the electrode, and unmeltedmixture 38 ahead which Is being progressively exposed to the arc.

Rapid cooling of the 'charge immediately following the fusion is madepossible by progressively exposing the unmelted charge directly to I theare, for in this way the previously melted material is not used totransmit heat to charge as yet unmelted, as is the case in conventionalfurnaces and crucibles. In the short time that the liquid state ismaintained, constituents which readily mix and dissolve in one anotherwill be- :ome thoroughly intermingled, but if the liquid state ismaintained for any appreciable time, :hose constituents (e. 8. copper)which do not nix readily will tend to separate from the renalnder of themetals and will form large aggrerations causing a non-uniformity in thefinaliroduct. By quickly moving the are away from my point just asfusion occurs, and then quickly drilling the fused substance, the metalsfreeze vhile still uniformly intermingled and before egregationtakesplace, thus resulting in a relaively uniform final structure.Furthermore, the otal duration of exposure at high temperatures ias beenreduced to a minimum so that loss of elements from oxidation orvaporization will .lso be held to a minimum. For the melting operation,there is used very itense' localized heat. -The electric arc is prearredto the acetylene torch because there is no last of gas to blow away thepowder and it is ossible to get a greater intensity of heat. As nexample, good results have been obtained with un'ents of 400-600'amperes at a potential of 30 olts. The are temperature is in theneighborood of 3,000 degrees centrigrade, which is well above themeltingpoint, or in many instances even the boiling point, of most substanceswhich' may be fused in the mould. This current pro.- vides an arc-havingsuch a large quantity of heat as to almost instantaneously melt themixture, regardless of variations in the size' or melting point of theindividual particles. The combination of high temperature and high heatoutput make negligible the difference in time of melting between largeand small pieces, or ones with high and low melting points. I

In practice, the electrode can be moved substantially continuously alongthe mould. When electrode 28 is hand operated, the rate of movement maynot be uniform, or the operator may temporarily move the electrodebackwards, but in general'its movement may be characterized as beingcontinuously forward, away from the molten portion of the charge, toprogressively expose unmelted portions of the charge to the arc. Therate of movement will depend on the energy output of the arc, the massof charge per unit length of the mould, and, to some extent, thefusibility of the charge. For example, other factors remaining constant,the electrode speed will vary with the spacing of faces 20a as thatcontrols the size of rod produced andhence the weight "of charge perinch to be melted. By proper regulation of these inter-related factors,control is exercised over the rate of melting, the time ofliquification, and the temperature of the melt.

The amount of oxidation will depend upon exposure to the atmosphere andthe amount and duration of high temperatures. Since the time of melting,the time of liquiflcation, and the time of congealing are all as shortas possible, the total time during which the substance is at asufflcient 1y h'gh temperature to oxidize is very short and littleoxidation takes place. The amount of oxidationmay be further reduced bypreventing contact with-the atmosphere through the presence of a neutralor reducing layer of gas over the fused body. This gas may be introducedas such by suitable means, or by vaporizing electrode 28, or by thevaporization of constiluents in the mixture to be fused. In practice,the tip of electrode 28 burns away slowly, and so there is present overthe charge an atmosphere containing. carbon vapor or carbon monoxidewhich results in a more or less neutral atmosphere. By using a specialelectrode this effect can be increased.

After a thorough mixing of the dry ingredients that will form thecharge, it is preferable, but not necessary, to add to the mixture about1% by weight of some combustible liquid that is not too volatile and 'ischemically inert relative to the :powdered materials. Addition of such aliquid is especially helpful in maintaining uniformity I when themixture contains flaky particles.

The moistening liquid is preferably combustible for it then has theeffect of reducing oxidation since it burns in the arc and forms a layerof neutral-products of combustionover the fusedmaterial. A combustiblehydro-carbon, for example kerosene or, turpentine, is particularlysuitable since it consumes the oxygen in the at "osphere immediatelyaround the arc and does not add any "oxygen to the mixture.

The condition may arise where one or more such,as tungsten carbide. Orone constituent constituents of the charge are diihcultly fusible,

may have a very low melting point. Under these circumstances it may bedesired to melt less than all, or only one, of the constituents. Thiscan be done by decreasing the current and consequently the heat output,or by moving the upper electrode more rapidly, or both. Thusthe broaderaspects of the invention include the formation of 'a solid body by,fusing one or more ingredients of a mixture and rapidly cooling thefused substancebefore separation of the other unmelted ingredients takesplace, so that a relatively uniform solid free'from large segregationsis produced.

The electric energy is used very eillciently for radiation losses aresmall, the time during which the metalis maintained liquid is short, andthere is no largemass of furnace, crucible, ormould to heat. As aresult, nearly all the heat supplied is used to melt the charge. a

Fig. 3 illustrates a device in which a plurality of mould units such as,have been already described are placed upon amovable support so thatthey may be successively moved past a given point. a plurality of theseunits 40 on a central table 42 which rotates about a vertical spindle43. In

this case, the operator uses a single movable electrode 28 but isstationed at one place so that the electrode has only a predeterminedrange of been completed in each unit it may then be moved on to asuccessive point where a second operator can remove the flnishedweldingrod and prepare the mould to receive another charge of mixture.Obviously, these mould units need not be placed upon a circular tablebut may be placed upon any suitable moving member which will pass thembefore a particular point; and the movable electrode may be machineoperated to move only longitudinaily of the mould, after the mould hasbeen moved into position beneath the electrode.

Fig. 4 illustrates diagrammatically a variational form of apparatus. Inthis form, the upper electrode 45 is mounted in a stationary bracket 48so that it is fixed in position. The mould is formed by a cavity in. ablock of carbonv 48 which rests upon a moving member 49 adapted to passblock 48 past electrode 45 so that the cavity therein moveslongitudinally relative to the upper electrode. In this construction,all the mould walls are formed by an electrode whic happensto be themovable one.

Obviously, the cavity in block 48 forming the mould or materialreceiving space may be of any suitable shape or configuration accordingto the shape of the final product. Also, the shape of both electrodesand the nature of the relative movement between them may be changed toconform suitably. to moulds having shapes other than herein illustrated.

In the event that it is desired to preheat the mixture, this may be doneby so attaching the power connection to the 'mould electrode that thecurrent will pass through the unfused substance .before the electrode isactually over it. For example, in Fig. 4 the lower electrode is movingtoward the left as-indicated by arrow ill so -that,the relative movementof stationary electrode 45 is toward the right as indicated by arro'wSI, and to preheatpowdered material 52 power connection 33 is attachedat 53 to the right hand end of the mould which is at a point removedfrom the upper. electrodein the direction of the latters movementrelative to the mould.

It has been found advantageous to mount The smaller the cross section ofthe lower electrodethe greater the heating effect will be, since theresistance, and consequently the temperature, of the electrode isinversely proportional to its cross sectional area. Under somecircumstances it may be desired to prevent .quick chilling bypost-heating the molten charge 55; and this can be accomplished eitherby'reversing the relative direction of movement of' electrodes 45 and 4.or by attaching the power connection to the oppositeor left hand and ofelectrode 48, so that the electric lead to the lower electrode is at apoint removed from the upper electrode in the direction opposite to thelatters movement relative to the mould.

Having described the improved method and. preferred forms of apparatusembody my invention, it will be realized that the disclosure of thedrawings and specification is to be considered as illustrative of ratherthan restrictive upon the broader claims appended hereto, for variouschanges may be made by those skilled in the art without departing fromthe spirit and scope of my invention. 7

I claim as my invention: a

l. The process 'of forming a substantially homogeneous solid body ofconstituents slightLv soluble in each other and present in amountsgreatly in excess of their mutual solubility, that includes forming anintimate and uniform mixture of the constituents, placing the mixture ina cool mould, progressively moving over and through the mixture anelectric are which rapidly melts entirely that small portion of themixintimate and uniform mixture of the constituentmetals, placing themixture in a cool -mould, progressively moving over and through themixture an electric are which rapidly melts entire- 1y that smallportion of the mixture surroundin the arc, but without materiallyheating the mould, and immediately chilling this small molten portion inthe cool mould as soon as the arc moves on, thus solidifying the'smallmolten portion I with all of its constituents in substantially the sameuniform distribution as in the initial mixture.

3. The process of forming an alloy of a ferrous base and copper in anamount greatly in excess of the amount soluble in the ferrous base, thatincludes forming an intimate and uniform mixture of the constituentmetals, placing the mixture in an open mould, progressively moving over.the mixture an electric are which rapidly melts to a fluid state asmall portion of the mixture. and quickly cooling the small moltenportion within the mould while the copper is substantially uniformlydistributed and before segregation of the copper takes place.

4. The process of forming an alloy of a ferrous base and copper in anamount greatly in excess 1 of the amount soluble in the ferrous base,that $081,088 7 ture on an electrode which forms a mould prostill on theelectrode with the copper substantially uniformly distributed and beforesegregation of the copper takes place. i

5. The process of forming a ferrous welding rod of an alloy includingcopper in an amount greatly in excess of the amount soluble in a ferrousbase, that includes forming an intimate and uniform'mixture of thecopper and the ferrous base; placing the mixture in an elongate mouldthe shape of the final rod; at one end of the mould striking an are froma single carbon electrode which rapidly melts a portion of the mixture,the are being of suflicient size to melt the v mixture across the fullwidth of the mould; then as soon as all the mixture initially exposed tothe arc is melted, moving the arc lengthwise of the mould toprogressively melt all the remaining mixture; and rapidly andprogressively cooling each molten portion as the electrode moves on sothat the rod solidifies and retains the substantially uniformdistribution of the copper throughout the rod.

. JOHN A. ZUBLIN.

